Tue September 17, 2013 By: Farhana Faru

Two balls A and B of masses 'm' and '2m' are in motion with velocities 2V and V respectively.Compare(I)their inertia(2)their momentum(3)the force needed to stop them in same time

Expert Reply
Romal Bhansali
Tue September 17, 2013
(i) Since, the mass of B is more, inertia of B will be more.
(ii) Momentum is p = mv
Thus, for A, pA = m×2V = 2mV
And, for B, pB = 2m×V = 2mV
Thus, momentum for both is same.
(iii) According to Newton's second law, force is rate of change of momentum.
Since, we have to stop both the masses, their final momenta is zero.
Thus, force for both masses to stop in same time will be same.
F = dp/dt = 2mV/dt
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